Anesthetics and analgesics are important components of an animal research program. It is required by law and it is our ethical responsibility to avoid and minimize pain and distress in animals undergoing research. NIEHS has a strong rodent surgery core that provides surgical services to those investigators whose research requires rodent surgery. All surgeons are well skilled with aseptic technique, gentle tissue handling, and rodent surgery in general. Part of the surgery planning is to provide adequate and complete anesthesia and analgesia. It is also important that the selection of the anesthetic or analgesic not interfere with the research goal. The research in ES102825-01 investigates the efficacy, safety, duration of effect, and reliability of various types of anesthetics and analgesics. This research broadens our understanding of anesthetics and analgesics in mice and rats-ensuring adequate pain relief without interfering with the principle animal users research. We evaluate commercially available veterinary products as well as investigating new ways of compounding analagesics for longer duration of action.